Author:Dr. P. Siva Bharathi, M.D (Peds), AB (USA).
Introduction: Syncope refers to a sudden and transient loss of consciousness and muscle tone, followed by complete recovery, usually caused by a sudden drop in heart rate and blood pressure, which reduces blood flow to the brain.
Most of the fainting episodes in children are benign, but rarely can it be due to serious cardiac conditions. It can cause injuries.
Presyncope:If there is sudden (temporary) dizziness or lightheadedness without any loss of consciousness then it is called presyncope.
- Symptoms:Children may experience the following prior to fainting.
- Paleness of skin
- Light Headedness
- Visual disturbances
- Nausea (feeling of vomiting)
- Excessive sweat
Causes for Syncope: Causes for syncope can be divided broadly into more common benign (non serious) causes and less common but serious causes.
Vasovagal Syncope (Common Fainting):This is the most common cause of fainting among children. This type of fainting occurs when the part of the nervous system that regulates heart rate and blood pressure malfunctions in response to a trigger, such as scary, embarrassing or uneasy situation and also during blood draws, coughing etc. This allows blood to pool in the legs, which decreases the blood available for the heart to pump and eventually decrease the blood pressure. Sometimes it can be caused by change in body posture (postural syncope).
Serious Conditions: Rarely some serious cardiac condition like heart rhythm problems or defect in the structure of the heart can cause disturbances in the rate, rhythm or cardiac output and can cause syncope.
Other Causes: Toxic (poison) ingestions, hypoglycemia (decreased sugar in the body), anemia can cause syncope.
Conditions that Mimic Fainting: Conditions that may mimic syncope include seizures, migraine conditions, hysteria/conversion disorders, hysteria etc.
- Medical History
- Warning signs like nausea or sweating, preceding the syncope- vasovagal syncope
- Sudden loss of consciousness with no warning signs- Heart rhythm problem.
- Fainting during exertion (physical activity) – obstruction to blood flow from heart (aortic stenosis or hypertrophic cardiomyopathy)
- Family history of early cardiac death less than 45 years – cardiac problems
- Previous syncopal events- vasovagal syncope.
- Physical Examination
- Blood pressure monitoring while lying down and standing – If abnormal postural syncope
- Abnormal hear sounds (murmur): Cardiac structural defects like aortic stenosis or hypertrophic cardiomyopathy.
- Medical test
- ECG: Gives a picture of the electrical activity of the heart. Helps to identify heart rhythm problems. A normal ECG does not necessarily rule out rhythm problems.
- Echo- Cardiogram: Helps to identify any structural defects of heart.
- EEG: This is done if the fainting episode is associated with seizure like activity. This test is rarely useful in diagnosing syncope.
- BLood Tests: To check for anemia, glucose level in blood etc.
If any serious cardiac cause has been identified then it has to be managed specifically, depending on the condition.
- Management of Vasovagal Syncope.
- Encourage additional salt and water intake.
- Encourage eating regularly
- Avoid triggers which precipitates fainting.
- Advise lying down flat if the kid sense the fainting, before loosing consciousness.
- Advise to intermittently contract the leg muscle if prolonged standing is needed (Helps pump the blood up from the legs)
Medications are used VERY RARELY if the syncope is recurrent and is occurring even with above measures. (Hydroflurocortisone 0.1mg BID or atenolol 1 – 2 mg/kg/day or pseudoephedrine 4mg/kg/day)